docs: def load_irac_psf(channel, show_progress=False):    # pragma: no cover
      """
      Load a Spitzer IRAC PSF image.
  
      Parameters
      ----------
      channel : int (1-4)
          The IRAC channel number:
  
            * Channel 1:  3.6 microns
            * Channel 2:  4.5 microns
            * Channel 3:  5.8 microns
            * Channel 4:  8.0 microns
  
      show_progress : bool, optional
          Whether to display a progress bar during the download (default
          is `False`).
  
      Returns
      -------
      hdu : `~astropy.io.fits.ImageHDU`
          The IRAC PSF in a FITS image HDU.
  
      Examples
      --------
      .. plot::
          :include-source:
  
          from astropy.visualization import LogStretch, ImageNormalize
          from photutils.datasets import load_irac_psf
          hdu1 = load_irac_psf(1)
          hdu2 = load_irac_psf(2)
          hdu3 = load_irac_psf(3)
          hdu4 = load_irac_psf(4)
  
          norm = ImageNormalize(hdu1.data, stretch=LogStretch())
  
          fig, ((ax1, ax2), (ax3, ax4)) = plt.subplots(2, 2)
          ax1.imshow(hdu1.data, origin='lower', interpolation='nearest',
                     norm=norm)
          ax1.set_title('IRAC Ch1 PSF')
          ax2.imshow(hdu2.data, origin='lower', interpolation='nearest',
                     norm=norm)
          ax2.set_title('IRAC Ch2 PSF')
          ax3.imshow(hdu3.data, origin='lower', interpolation='nearest',
                     norm=norm)
          ax3.set_title('IRAC Ch3 PSF')
          ax4.imshow(hdu4.data, origin='lower', interpolation='nearest',
                     norm=norm)
          ax4.set_title('IRAC Ch4 PSF')
          plt.tight_layout()
          plt.show()
      """
  
      channel = int(channel)
      if channel < 1 or channel > 4:
          raise ValueError('channel must be 1, 2, 3, or 4')
  
      fn = 'irac_ch{0}_flight.fits'.format(channel)
      path = get_path(fn, location='remote', show_progress=show_progress)
      hdu = fits.open(path)[0]
  
      return hdu